Mobile elevating scaffolds

ABSTRACT

A mobile elevating scaffold includes an elongated scaffold platform or walkway which is supported by a scaffold frame structure which can be raised or lowered within a fixed upright frame structure mounted on a truck chassis. Movement of the scaffold frame structure is effected by first and second cables extending from winch drums mounted on the chassis and over first and second primary cable pulleys and terminally connected to the scaffold frame structure to provide a two-point suspension for that structure. The scaffold platform or walkway is usefully longitudinally adjustably supported on arms extending transversely outwardly from the scaffold frame structure.

United States Patent [I51 3,638,757

Sampson 1 Feb. 1, 1972 MOBILE ELEVATING SCAFFOLDS R .24,100 12/1955 Solomon ..l82/l45 [72] Inventor: Ralph D. Sampson, 145 Penfreld St., Primary Ex amt-n er Rcina1do R Machado Guelph Ontario Canada Attorney-W. Britton Moore [22] Filed: May 22, 1970 W [57] ABSTRACT [21] Appl. No.: 39,614

A mobile elevating scaffold includes an elongated scaffold platfonn or walkway which is supported by a scaffold frame [52] US. Cl ..l82/63, 182/ 145 structure which can be raised or lowered within a fixed upright [51] Int. Cl ..E04g 1/ 18 frame structure mounted on a truck chassis. Movement of the [58] Field of Search ..182/63, 145, 146, 127, 223 scaffold frame structure is effected by first and second cables extending from winch drums mounted on the chassis and over [56] R g Ci d first and second primary cable pulleys and terminally connected to the scaffold frame structure to provide a two-point UNlTED STATES PATENTS suspension for that structure. The scaffold platform or walkway is usefully longitudinally adjustably supported on arms ex- 3'493O79 2/1970 DmlschPs l82/63 tending transversely outwardly from the scaffold frame struc- 2,890,082 6/1959 McDaniel 182/63 mm 2,965,191 12/1960 Balogh ...l82/63 1,811,652 6/1931 Schuh 1 82/145 9 Claims, 8 Drawing Figures PATENIED FEB I 1972 SHEET 1 OF 3 INVENTOR RALPH D. SAMPSON ATTORNEY PATENTED FEB 1 1972 SHEEY 3 [IF 3 N O S P m ms D w mL A R MOBILE ELEVATING SCAFFOLDS BACKGROUND OF THE INVENTION The present invention relates to an elevating scaffold or platform and more particularly to an elevating scaffold mounted on a truck and especially suited for providing an elevated work platform adjacent an upright building. Although the elevating scaffolds of this invention are particularly suited for use by workmen carrying out servicing operations, such as painting, on buildings, the invention is in no way restricted to any specific use of the novel scaffolds now provided.

Many previously known elevating scaffolds have included the use of lazy-tong mechanisms for moving a working platform between lowered and elevated positions but such mechanisms are not only somewhat expensive to construct and maintain but are also relatively restricted in the extent of the elevation which they can provide unless unusually complex structures are utilized. Accordingly, such previously proposed elevating scaffolds have found only very limited acceptance in many fields. This is particularly true in the case of small businesses, such as those involved in house painting and the installation of siding, when the capital investment for such a vehicle would be prohibitive.

It is an object of this invention to provide an elevating scaffold which includes a scaffold. platform which can be moved between a raised and lowered position. Yet another object of this invention is to provide an elevating scaffold of the aforementioned type and which is relatively simple in its construction and of comparatively low cost.

Yet another object of this invention is to provide an elevating scaffold which can be installed on a conventional pickup truck not requiring extensive modifications of the chassis or drive system of such a vehicle.

Another object of this invention in accordance with a particularly useful feature thereof is to provide an elevating scaffold of the aforementioned type and which includes an elongated scaffold platform which is longitudinally adjustably supported so that a workman can service a much greater length of a building without having to move the elevating structure bodily along the ground.

Other objects of the invention will become apparent as the description herein proceeds.

SUMMARY OF THE INVENTION In its broadest scope, the present invention provides an elevating scaffold which comprises a chassis structure; an upright frame structure secured to said chassis structure and extending upwardly therefrom; a scaffold frame guidedly mounted on said upright frame structure for vertical guided movement thereon relative to said chassis structure; a scaffold platform supportedly mounted on said scaffold frame; a winch mounted on said chassis structure; first and second primary cable pulleys mounted on said upright frame structure up wardly of said winch; and first and second cables extending from said winch and over said first and second cable pulleys respectively and terminally secured to said scaffold frame at longitudinally spaced apart positions thereon to provide a twopoint suspension for said scaffold frame, whereby, on operation of said winch, the vertical position of said scaffold platform relative to said chassis structure is adjusted.

In accordance with a particularly useful feature of this invention, the scaffold platform thereof is longitudinally adjustably supported on the scaffold frame for the reason already set down herein.

Other features and advantages of the invention will become apparent as the description herein proceeds.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described merely by way of illustration with reference to the accompanying drawings in which;

FIG. 1 is a side elevation of a particularly useful embodiment of an elevating scafiold in accordance with this invention, certain parts being shown cut away or fragmentarily to reveal otherwise concealed structural components;

FIG. 2 is a front end elevation of the elevating scaffold of FIG. 1 with certain parts being cut away to reveal otherwise concealed structural components;

FIG. 3 is a somewhat schematic side elevation of the elevating scaffold of FIGS. 1 and 2 showing the manner in which a scaffold platform of such an elevating scaffold is, in accordance with a particularly useful feature of this invention, longitudinally adjustably supported by a scaffold frame of the elevating scaffold;

FIG. 4 is an enlarged fragmentary perspective view of a winch provided on the elevating scaffold of the preceding figures and additionally showing an electric motor provided for operating such winch, when viewed as indicated by the arrows 4-4 of FIG. 2;

FIG. 5 is an enlarged fragmentary perspective view of one upright frame structure of the elevating scaffold of FIGS. 1 to 3 and also showing fragmentarily one tubular sleeve of a scaffold frame of that elevating scaffold, when viewed as indicated by the arrows 55 of FIG. 2;

FIG. 6 is a perspective view from above and partly from one side and from the front of the elevating scaffold of the preceding figures of the drawings;

FIG. 7 is an enlarged fragmentary perspective view of intermediate cable pulleys provided on the elevating scaffold of the preceding figures when viewed as indicated by the arrows 7 7 of FIG. 6; and

FIG. 8 is an enlarged fragmentary perspective view of one pair of primary cable pulley wheels provided on the elevating scaffold of the preceding figures when viewed as indicated by the arrows 88 of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS It will be seen that the particularly useful embodiment of an elevating scaffold in accordance with this invention as indicated generally at 10 in the accompanying drawings in constructed on a pickup truck 9 having a chassis frame which is reinforced by longitudinal members 11 and 12 interconnected at their front and rear ends by transverse members 13 and 14 respectively. The frame members 11, 12, 13, and I4 constitute a chassis structure or base frame on which the elevating scaffold is mounted in a manner yet to be described.

The elevating scaffold 10 also includes an upright frame structure generally indicated at 16 and including front and rear tubular posts 17 and 18 respectively which are mounted on the chassis frame members 13 and 14 respectively. A scaffold frame generally indicated at 19 and longitudinally adjustably supporting a scaffold platform generally indicated at 20 is mounted in the upright frame structure 16 in a manner which will be described hereinafter in greater detail for vertical guided movement of the scaffold frame 19 and consequently of the scaffold platform 20 relative to the chassis frame structure and as indicated by the double-headed arrow A in FIG. 2. Such vertical movement of the scaffold frame 19 and of the scaffold platform 20 is effected by a winch generally indicated at 22 and mounted under the bed of the truck and which is operative to take up or pay out cables 23 and 24 which are terminally secured to the scaffold frame 19 and which extend over respective first and second primary cable pulleys generally indicated at 25 and 26 respectively and mounted on the upper ends of the front and rear tubular posts 17 and 18 respectively.

The pickup truck 9 shown in the accompanying drawings includes a conventional chassis and drive system but the former is, as already explained, strengthened to support the elevating scaffold 10 of the invention. As already explained, the chassis of the truck is reinforced by the provision of the additional chassis frame members 11, l2, l3 and 14. Since the body work of the truck forms no essential part of this invention, it will not, therefore, be described in greater detail herein. It can, however, be noted that such body work includes a cab portion generally indicated at 28 which is transversely offset at the front end of the vehicle. The truck also includes a loading bed 29 below which the winch 22 is suitably mounted and in the sides of which various compartments such as those indicated at 30 and 31 may usefully be provided for accommodating tools, electrical cables and other auxiliary equipment.

The elevating scaffold shown in the accompanying drawing is particularly intended for use during the installation of prefabricated siding on buildings and, for this reason, the truck 9 is shown in the accompanying drawings as being provided with a retractably mounted brake 32 by the use of which siding panels may be formed to a required shape. Since such a brake press, however, forms no part of this invention, it will not be described in greater detail herein.

Referring now in greater detail to the upright frame structure 16, it will be seen that this structure includes the aforementioned front and rear tubular posts 17 and 18 respectively which are secured, for example, by welding to respective one of the front and rear transverse members 13 and 14, and an intermediate upstanding frame member 34 which extends through the bed 29 of the truck 9 and is secured, for example, by welding, at its lower end to the longitudinal member 12 as will best be understood by reference to FIG. 2.

Short angle members 35 and 36 are secured, for example, by welding, to the upper ends of respective ones of the upright tubular posts 17 and 18 so as to extend transversely inwardly therefrom. The upright frame structure is essentially completed by diagonal-tubular-bracing struts 37 and 38 which are connected, for example, by welding, between the upper end of the intermediate upstanding frame member 34 and the inner ends of the angle members 35 and 36 respectively. It should perhaps be indicated at this juncture that the angle members 35 and 36 are positioned on the posts 17 and 18 respectively so that they do not project longitudinally inwardly or transversely outwardly of the corresponding surfaces of the posts 17 and 18.

Referring now in greater detail to the scaffold frame 19, it will be seen that that frame 19 includes tubular sleeves 40 and 41 which are coaxiaily disposed around the front and rear upright posts 17 and 18 respectively of the upright frame structure 16 for guided vertical movement along such posts. The sleeves 40 and 41 are integrally formed with upwardly extending, elongated partial sleeves 42 and 43 respectively which extend partially around the respective posts 17 and 18 so as to be guided thereby while allowing movement of such partial sleeves 42 and 43 upwardly past the angle members 35 and 36 secured to the upper ends of the posts 17 and 18 and past the front and rear primary cable pulleys 25 and 26 as will best be understood by reference to FIGS. 2'and 6 of the accompanying drawings.

In proximity to their upper ends, the partial sleeves 42 and 43 are interconnected and held in position partially around the respective ones of the posts 17 and 18 by upper and lower, transversely inwardly extending shelves 46 and 47 respectively. Each such shelf is secured to the partial sleeves 42 and 43 by angle members 48 which are suitably welded to respective ones of the partial sleeves 42 and 43 and which have the shelves 46 and 47 secured thereto, for example, by bolting. Further structural support for the scaffold frame 19 is provided by a backing 50 secured across the transverse inner edges of the shelves 46 and 47. The backing 50 extends upwardly beyond the upper shelf 46 and serves to retain stacks 51 of siding panels in position on the shelves as shown in H0.

Also secured to the aforementioned partial sleeves 42 and 43 and disposed a short distance below the lower shelf 47, there are provided front and rear, transversely outwardly extending arms 52 and 53 on which the aforementioned scaffold platform is longitudinally adjustably supported. Each of the arms52 and 53 is disposed below the platform 20 and is provided at its outer edge with an inwardly extending lug 55 which slidably engages the outer edge of the upper surface of the platform 20. Short angled members 54 secured to the partial sleeves 42 and 43 upwardly of the arms 52 and 53 respectively serve similarly slidably to engage the inner edge of the upper surface of the scaffold platform 20. In this way, accidental tipping of the platform 20 is totally prevented.

As already explained, the winch 22 is mounted below the bed 29 of the truck 9 and, from FIGS. 2 and 4 of the drawings, it will be seen that the winch 22 includes two winch drums 58 and 59 carried by a common shaft 60 which is suitably journaled in upstanding bearing plates 61, 62 and 63. The shaft 60 is driven through a slipping clutch mechanism 64 of any conventional type by a belt 65 which is, in turn driven by an electric motor 66. The motor 66 is suitably mounted on a baseplate 67 secured to a transversely extending mounting plate 68 to which the aforementioned bearing plates 61, 62 and 63 are secured, suitably be welding. The mounting plate 68 is in turn supported by suitable frame members 69, 70 and 71 in turn mounted on the hereinbefore described chassis structure in any appropriate manner.

The electric motor 66 is usefully of a reversible type which can be energized from a domestic electrical supply system and, in the particular structure illustrated in the accompanying drawings, operation of the motor 66 is controlled by a reversible manual switch 72 mounted on a bracket 73 secured to the undersurface of lower shelf 47 to permit its operation by a person standing on the scaffold platform 20. Electrical cables 74 and 75 interconnect the switch 72 and the motor 66 while a male electrical connector 76 (FIG. 1) is usefully provided in the aforementioned compartment 31 for connection to an extension cord (not shown). Such as extension cord may, when not in use, conveniently be stored within one of the compartments 30 and 31. An electrical socket outlet 77 is also usefully provided for the connection of electric handtools by personnel working from the truck 9.

Referring now in greater detail to the cables 23 and 24, it will be seen that these cables extend upwardly from the winch drums 58 and 59 respectively through openings 78 in the bed 29 of the truck 9 to intermediate pulley wheels 79 and 80 respectively (FIG. 7) rotatably mounted on a shaft 81 carried by lugs 82 and 83 secured, for example, by welding, to a short angle member 84 in turn secured, for example, by welding, to the upper end of the aforementioned intermediate upstanding frame member 34 and extending transversely outwardly therefrom. From the pulley wheels 79 and 80, the cables 23 and 24 respectively diverge upwardly and longitudinally to the aforementioned front and rear primary cable pulleys 25 and 26 respectively.

Since the primary cable pulleys 25 and 26 have essentially identical structures, other than being mere mirror images of each other, the structure of only one such primary cable pulley will now be described. From FIG. 8, it will be seen that the primary cable pulley 25 includes first and second pulley wheels 86 and 87 respectively mounted on shafts suitably mounted in turn in brackets 88 and 99 respectively secured to the aforementioned angle member 35. The axes of the pulley wheels 86 and 87 are anguiarly disposed to each other so that pulley wheel 86 is aligned with the cable 23 extending upwardly and forwardly from the aforementioned pulley wheel 79 while the pulley wheel 87 is disposed in a generally vertical plane. A simple cover 90 is usefully provided over each of the front and rear primary cable pulleys 25 and 26 res ectively to prevent damage to such pulleys and to reduce the risk of injury to personnel. From the second pulley wheels 87 of the primary cable pulleys 25 and 26, the cables 23 and 24 respectively extend generally vertically downwardly to a respective one of the aforementioned sleeves 40 and 41 and to which they are terminally secured by means of a conventional hook-and-eye arrangement as indicated generally at 91 in FIG. 5.

Having completed the description of the structure of the elevating scaffold 10 shown in the accompanying drawings, its manner of operation will now be briefly summarized. it will readily be understood, that, by operating the switch 72, a workman standing on the scaffold platform 20 can cause operation of the electric motor 66 to rotate the winch drums 58 and 59 in either desired direction. Such rotation of the winch drums 58 and 59 causes the cables 23 and 24 respectively either to be paid out or taken up and consequently causes lowering or raising respectively of the scaffold platform 20 between the lowermost position thereof as shown in FIGS. 1 and 6 and in solid lines in FIG. 2 and the uppermost position thereof as indicated in broken lines at 20 in FIG. 2, an intermediate position being shown at 20".

During such raising or lowering of the scaffold platform 20 in the described manner, the scaffold frame 19 is guidedly supported by engagement of the stationary front and rear tubular posts 17 and 18 with both the sleeves 40 and 41 respectively and with both the partial sleeves 42 and 43 respectively. It will now be understood why the angle members 35 and 36 are secured to the posts 17 and 18 respectively so as to be clear of the partial sleeves 42 and 43 respectively. The full sleeves 40 and 41, however, serve to prevent upward movement of the scaffold platform 20 beyond its uppermost position. The slipping clutch mechanism 64 is effective to prevent damage to the motor 66 in the event that the switch 72 is operated after the scaffold platform 20 has reached its lowermost and uppermost positions.

In accordance with a particularly useful feature of this invention, the scaffold platform 20 is usually longitudinally adjustably supported on the scaffold frame 19. The manner of such longitudinal adjustment will best be understood by reference to FIG. 3 from which it will be seen that the scaffold platform 20 can be moved longitudinally as indicated by the double-headed arrow B over the front and rear supporting arms 52 and 53 respectively from the solid-line position indicated at 20 to the broken line position indicated at 20" to provide a workman with a much greater working length without requiring him to move the truck 9 over the ground.

Although the invention is in no way restricted to any specific dimensions, it may usefully be noted that an elevating scaffold has been constructed essentially as illustrated in the accompanying drawings and with the posts 17 and 18 each having a vertical height of about feet. A maximum elevation for the scaffold platform (top surface level) of about 24 feet was obtained with this particular structure. It will be appreciated that such a height is quite sufficient for use in working on a conventional two-story building, for example, for applying siding to such a building or for painting purposes. The overall length of the scaffold platform 20 of the particular structure built was 22 feet and gave a total working length of about 30 feet.

What I claim is:

1. An elevating scaffold which comprises:

a chassis structure;

an upright frame structure including first and second, longitudinally spaced apart upright posts secured to said chassis structure and extending upwardly therefrom;

a winch mounted on said chassis structure;

first and second primary cable pulleys mounted on respective ones of said first and second upright posts upwardly of said winch;

a scaffold frame including first and second sleeves coaxially disposed about respective ones of said first and second upright posts and integrally formed with respective, upwardly extending and elongated partial sleeves which extend partially around respective ones of said first and second upright posts for generally vertical-guided movement relative thereto past respective ones of said first and second primary cable pulleys;

of said winch, the vertical position of said scaffold platform relative to said chassis structure 15 ad usted between a lowermost position and an uppermost position in which said scaffold platform is elevated above said first and second primary cable pulleys.

2. An elevating scaffold as claimed in claim 1 in which said scaffold platform is longitudinally adjustably supported on first and second, longitudinally spaced apart and transversely extending support arms secured to said scaffold frame.

3. An elevating scaffold as claimed in claim 2 in which said first and second cables are terminally secured to respective ones of said first and second sleeves and in which said support arms are directly mounted on respective ones of said partial sleeves.

4. An elevating scaffold as claimed in claim 3 in which said winch is disposed generally longitudinally centrally of said first and second upright posts of said upright frame structure.

5. An elevating scaffold as claimed in claim 3 in which said upright frame structure includes an intermediate upstanding frame member supported on said chassis structure between said first and second upright posts of said upright frame structure and first and second diagonal bracing struts diverging longitudinally and upwardly from said intermediate upstanding frame member and interconnecting said intermediate upstanding frame member and respective ones of said first and second upright posts of said upright frame structure, which elevating scaffold additionally includes first and second intermediate cable pulleys mounted on said intermediate upstanding frame member upwardly of said winch, and in which elevating scaffold said first and second cables extend upwardly from said winch round respective ones of said intermediate cable pulleys to respective ones of said primary cable pulleys.

6. An elevating scaffold as claimed in claim 5 in which said upright frame structure is mounted on said chassis structure in proximity to one transverse side thereof while said winch is mounted on said chassis structure transversely inwardly of said upright frame structure, and in which each of said first and second primary cable pulleys comprises a pair of mutually angularly disposed pulley wheels adapted to guide respective ones of said first and second cables extending therefrom both transversely inwardly to respective ones of said intermediate cable pulleys and generally vertically downwardly to respective ones of said first and second sleeves of said scaffold frame.

7. An elevating scaffold as claimed in claim 6 in which said scaffold frame has at least one transversely inwardly projecting, article-supporting shelf mounted thereon for conjoint vertical movement with said scaffold platform.

8. An elevating scaffold as claimed in claim 7 in which said chassis structure comprises a chassis frame of a motor vehicle and in which said winch is operatively associated with an electric motor adapted controllably to be operated from a domestic electrical supply system.

9. An elevating scaffold as claimed in claim 8 in which said electric motor has operatively connected thereto a reversible manual control switch for controlling operation of said winch and in turn elevation and lowering of said scaffold platform and in which said control switch is mounted on said scaffold frame for operation by a person on said scaffold platform. 

1. An elevating scaffold which comprises: a chassis structure; an upright frame structure including first and second, longitudinally spaced apart upright posts secured to said chassis structure and extending upwardly therefrom; a winch mounted on said chassis structure; first and second primary cable pulleys mounted on respective ones of said first and second upright posts upwardly of said winch; a scaffold frame including first and second sleeves coaxially disposed about respective ones of said first and second upright posts and integrally formed with respective, upwardly extending and elongated partial sleeves which extend partially around respective ones of said first and second upright posts for generally vertical-guided movement relative thereto past respective ones of said first and second primary cable pulleys; a scaffold platform supportedly mounted on said scaffold frame; and first and second cables extending from said winch and over said first and second cable pulleys respectively and terminally secured to said scaffold frame at longitudinally spaced apart positions thereon to provide a two-point suspension for said scaffold frame, whereby, on operation of said winch, the vertical position of said scaffold platform relative to said chassis structure is adjusted between a lowermost position and an uppermost position in which said scaffold platform is elevated above said first and second primary cable pulleys.
 2. An elevating scaffold as claimed in claim 1 in which said scaffold platform is longitudinally adjustably supported on first and second, longitudinally spaced apart and transversely extending support arms secured to said scaffold frame.
 3. An elevating scaffold as claimed in claim 2 in which said first and second cables are terminally secured to respective ones of said first and second sleeves and in which said support arms are directly mounted on respective ones of said partial sleeves.
 4. An elevating scaffold as claimed in claim 3 in which said winch is disposed generally longitudinally centrally of said first and second upright posts of said upright frame structure.
 5. An elevating scaffold as claimed in claim 3 in which said upright frame structure includes an intermediate upstanding frame member supported on said chassis structure between said first and second upright posts of said upright frame structure and first and second diagonal bracing struts diverging longitudinally and upwardly from said intermediate upstanding frame member and interconnecting said intermediate upstanding frame member and respective ones of said first and second upright posts of said upright frame structure, which elevating scaffold additionally includes first and second intermediate cable pulleys mounted on said intermediate upstanding frame member upwardly of said winch, and in which elevating scaffold said first and second cables extend upwardly from said winch round respective ones of said intermediate cable pulleys to respective ones of said primary cable pulleys.
 6. An elevating scaffold as claimed in claim 5 in which said upright frame structure is mounted on said chassis structure in proximity to one transverse side thereof while said winch is mounted on said chassis structure transversely inwardly of said upright frame structure, and in which each of said first and second primary cable pulleys comprises a pair of mutually angularly disposed pulley wheels adapted to guide respective ones of said first and second cables extending therefrom both transversely inwardly to respective ones of said intermediate cable pulleys and generally vertically downwardly to respective ones of said first and second sleeves of said scaffold frame.
 7. An elevating scaffold as claiMed in claim 6 in which said scaffold frame has at least one transversely inwardly projecting, article-supporting shelf mounted thereon for conjoint vertical movement with said scaffold platform.
 8. An elevating scaffold as claimed in claim 7 in which said chassis structure comprises a chassis frame of a motor vehicle and in which said winch is operatively associated with an electric motor adapted controllably to be operated from a domestic electrical supply system.
 9. An elevating scaffold as claimed in claim 8 in which said electric motor has operatively connected thereto a reversible manual control switch for controlling operation of said winch and in turn elevation and lowering of said scaffold platform and in which said control switch is mounted on said scaffold frame for operation by a person on said scaffold platform. 